Visualizing DC morphology and T cell motility to characterize DC-T cell encounters in mouse lymph nodes under mTOR inhibition
- 68 Downloads
Mammalian target of rapamycin (mTOR), a serine/threonine kinase orchestrating cellular metabolism, is a crucial immune system regulator. However, it remains unclear how mTOR regulates dendritic cell (DC) function in vivo, especially DC-T cell encounters, a critical step for initiating adaptive immune responses. We dynamically visualized DC-T contacts in mouse lymph node using confocal microscopy and established an encounter model to characterize the effect of mTOR inhibition on DC-T cell encounters using DC morphology. Quantitative data showed mTOR inhibition via rapamycin altered DC shape, with an increased form factor (30.17%) and decreased cellular surface area (20.36%) and perimeter (22.43%), which were associated with Cdc42 protein downregulation (52.71%). Additionally, DCs adopted a similar morphological change with Cdc42 inhibition via ZCL278 as that observed with mTOR inhibition. These morphologically altered DCs displayed low encounter rates with T cells. Time-lapse imaging data of T cell motility supported the simulated result of the encounter model, where antigen-specific T cells appeared to reduce arrest in the lymph nodes of rapamycin-pretreated mice relative to the untreated group. Therefore, mTOR inhibition altered DC morphology in vivo and decreased the DC-T cell encounter rate, as well as Cdc42 inhibition. By establishing an encounter model, our study provides an intuitive approach for the early prediction of DC function through morphological quantification of form factor and area.
KeywordsmTOR intravital imaging DC-T contacts Cdc42 inhibition
We thank the Optical Bioimaging Core Facility of WNLO-HUST for the support in data acquisition. This work was supported by the Science Fund for Creative Research Groups of the National Natural Science Foundation of China (61721092), the Major Research Plan of the National Natural Science Foundation of China (91542000, 91442201), National Science Fund for Distinguished Young Scholars (81625012), National Natural Science Foundation of China (81501593), and the Director Fund of WNLO.
Compliance and ethics The author(s) declare that they have no conflict of interest.
- Abbas, A.K., Lichtman, A.H., and Pillai, S. (2014). Cellular and Molecular Immunology, 8th ed. (Philadelphia, PA: Elsevier).Google Scholar
- Alieva, M., Ritsma, L., Giedt, R.J., Weissleder, R., and van Rheenen, J. (2014). Imaging windows for long-term intravital imaging. Intra Vital 3, e29917.Google Scholar
- Haidinger, M., Poglitsch, M., Geyeregger, R., Kasturi, S., Zeyda, M., Zlabinger, G.J., Pulendran, B., Hörl, W.H., Säemann, M.D., and Weichhart, T. (2010). A versatile role of mammalian target of rapamycin in human dendritic cell function and differentiation. J Immunol 185, 3919–3931.CrossRefGoogle Scholar
- Iqbal, A.J., McNeill, E., Kapellos, T.S., Regan-Komito, D., Norman, S., Burd, S., Smart, N., Machemer, D.E.W., Stylianou, E., McShane, H., et al. (2014). Human CD68 promoter GFP transgenic mice allow analysis of monocyte to macrophage differentiation in vivo. Blood 124, e33–e44.CrossRefGoogle Scholar
- Qi, S., Li, H., Lu, L., Qi, Z., Liu, L., Chen, L., Shen, G., Fu, L., Luo, Q., and Zhang, Z. (2016). Long-term intravital imaging of the multicolorcoded tumor microenvironment during combination immunotherapy. eLife 5, e14756.Google Scholar
- Sordi, V., Bianchi, G., Buracchi, C., Mercalli, A., Marchesi, F., D’Amico, G., Yang, C.H., Luini, W., Vecchi, A., Mantovani, A., et al. (2006). Differential effects of immunosuppressive drugs on chemokine receptor CCR7 in human monocyte-derived dendritic cells: selective upregulation by rapamycin. Transplantation 82, 826–834.CrossRefGoogle Scholar
- Speranza, L., Giuliano, T., Volpicelli, F., De Stefano, M.E., Lombardi, L., Chambery, A., Lacivita, E., Leopoldo, M., Bellenchi, G.C., di Porzio, U., et al. (2015). Activation of 5-HT7 receptor stimulates neurite elongation through mTOR, Cdc42 and actin filaments dynamics. Front Behav Neurosci 9, 62.CrossRefGoogle Scholar
- Stein, J.V. (2015). T cell motility as modulator of interactions with dendritic cells. Front Immunol 6.Google Scholar
- Sukhbaatar, N., Hengstschläger, M., and Weichhart, T. (2016). mTORmediated regulation of dendritic cell differentiation and function. Trends Immunol 37, 778–789.Google Scholar
- Weichhart, T., Haidinger, M., Katholnig, K., Kopecky, C., Poglitsch, M., Lassnig, C., Rosner, M., Zlabinger, G.J., Hengstschläger, M., Müller, M., et al. (2011). Inhibition of mTOR blocks the anti-inflammatory effects of glucocorticoids in myeloid immune cells. Blood 117, 4273–4283.CrossRefGoogle Scholar